Described is a needle assembly (4) comprising a needle (4.1) and a needle hub (4.2) adapted to carry the needle (4.1). The needle hub (4.2) includes a proximal portion (4.3) adapted to engage a medicament delivery device (2) having a first thread (2.2) and a cover portion (4.5) adapted to abut a distal surface (2.3) of the delivery device (2). The proximal portion (4.3) includes a second thread (4.4) adapted to engage the first thread (2.2), and the second thread (4.4) is offset from the cover portion (4.5) by a first distance (a).
